JPS59147763A - Production of aluminum alloy casting - Google Patents

Abstract

PURPOSE:To obtain efficiently an Al alloy casting having excellent product strength by filling under pressure a molten Al alloy into dies under a specific condition, removing the casting upon solidification before the temp. thereof falls down to a specified temp. and subjecting the casting to a hardening treatment. CONSTITUTION:A molten Al alloy is filled under pressure in the cavity of dies under the condition of <=300kg/cm<2> casting pressure and <=3m/sec gate speed. The casting is removed from the dies at the point of the time when the casting temp. does not fall down to <=350 deg.C upon solidification and the casting is immediately hardened in water, etc. to fix the supersaturated state. The casting is further subjected to an artificial aging treatment to improve the strength thereof according to need. The generation of a blowhole and blister is suppressed by such a method and the Al alloy casting having high strength is obtd. The method is applicable to the production of the cylinder head of an internal-combustion engine, parts for a cooler, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for casting various parts made of aluminum alloy.

2. Description of the Related Art As a method for manufacturing aluminum alloy castings such as cylinder heads of internal combustion engines or parts for coolers, either die casting or gravity casting has been conventionally employed. In die casting, the molten metal is filled into the mold at high speed and high pressure, so production efficiency is good, but
It has the disadvantage that gas is easily drawn in during casting, forming cavities, and when heat treatment is performed after casting to obtain the necessary strength, blisters are likely to occur due to the contained gas.
Parts that require a certain level of strength, such as cylinder heads, are generally subjected to T6 treatment after gravity casting. That is, as shown in Fig. 2, after casting, the casting is allowed to cool naturally as indicated by line a, and then as shown in line segment 5.
A solution treatment is carried out to bring the alloying elements into a supersaturated solid solution state by heating to around 00°C, and then, as shown by line C, the alloying elements are precipitated and hardened by artificial aging.

However, with the above method, the production efficiency is inferior to the die-casting method because gravity casting is first performed, and after casting, a step of reheating the cooled casting is required for solution treatment. As the number of steps increases, space for heating, equipment, energy for heating, etc. are required. Therefore, there are disadvantages in terms of production efficiency and thermoeconomics.

The present invention has been developed in view of the above-mentioned conventional problems, and it is possible to reduce the number of manufacturing steps, obtain the same strength as solution treatment, and also be advantageous in terms of production efficiency and thermoeconomics. The purpose of the present invention is to provide a method for manufacturing aluminum alloy castings.

In order to achieve this object, the first invention according to the present application includes a step of filling a mold with molten aluminum alloy under conditions of a casting pressure of 300 m/sec or less and a gate speed of 3 m/sec or less, and solidifying the filled molten metal. The gist is that the process consists of a step of removing the casting from the mold before the temperature drops to 350°C or less after cooling, and a step of immediately quenching the removed casting.
Moreover, the gist of the second invention is that an artificial aging treatment step is added following the above-mentioned quenching step.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a mold for casting an aluminum alloy casting according to the present invention. The mold 1 has a lower core 3 on a die base 2.
In addition, the main cores 5 are respectively fixed to the movable plate 4, and the sliding cores 6 are arranged between the lower cores 3 and the main cores 5, and the cores 3, 5 are held in a mold-clamped state. , 6, a cavity 7 is formed between them. And to perform casting, the molten metal inlet 8. After injecting the molten metal, the inlet []8 is closed with a seal 9, and then the Teflanger 10 is raised to fill the cavity γ with molten metal 1ν■. Thereafter, the core is released and the solidified casting is taken out using the push-out pins 11.

In the present invention, the casting conditions described in -F are set at a low casting pressure of 3ooTiylcr& or less and a low gate speed of 3 m/sec or less. By filling the molten aluminum alloy at low pressure and speed in this way, heat treatment is possible because there are few gases and cavities, and no blisters occur even at high temperatures. It becomes possible to take out the IT casting from the mold.

Therefore, the casting solidified in the mold is taken out at a temperature of 350° C. or higher, and immediately quenched in water as shown by line d in FIG. This rapid cooling makes it possible to fix a sufficient supersaturated state.

Furthermore, following this quenching step, it is also possible to perform artificial aging treatment to increase the strength of the casting.

As described above, the present invention is designed to rapidly cool a casting in a high temperature state, and the same effect as that obtained by solution treatment can be obtained.

Next, a specific experimental example will be described and compared with conventional casting.

[Experiment Example 1] First, using a mold as shown in Fig. 1, molten aluminum alloy (equivalent to JIS AC2B) was heated to a temperature of 720°C.
Casting pressure 27oR, yAr&, gate speed 06m/see
The mold was filled under pressure under the following casting conditions and cooled in the mold for 13 seconds. Next, the solidified casting was taken out at a temperature of 360°C 7,
It was immediately immersed in water and quenched.

The hardness of the product thus obtained is HRF 88.9
Met.

In contrast, a product manufactured by conventional gravity casting and then subjected to T4 treatment has a hardness of HRF 87.0.

[Experiment Example 2] In order to manufacture parts for car coolers, aluminum alloy (
JIS ADC-10 equivalent) molten metal at a temperature of 700℃,
Casting pressure 2401 (yc), gate speed 0.8 m/se
It is pressurized and filled into the mold under the casting conditions of c, and cooled in the mold for 15 seconds. Then, the solidified casting was taken out when the temperature reached 350°C, and immediately quenched in water. After this, the pages were subjected to artificial aging treatment at 175°C for 6 hours.

Table 1 shows a comparison between the product thus obtained and a conventional product subjected to T6 treatment.In the table, T6 indicates that artificial aging treatment was applied after solution treatment, and CQ is This indicates that the treatment according to the first invention of the present application has been performed, and T5 indicates that the artificial aging treatment has been performed.

[Table 1] As is clear from this [Table 1], the products obtained by the present invention had a strength close to that of conventional products.

Furthermore, the product obtained by the first invention of the present application (CQ) and the product obtained by the second invention (CQ+T5) were compared with the as-cast product F and the conventional product T6 which was subjected to artificial aging after solution treatment. Other experimental results are shown in [Table 2]○ As is clear from [Table 2], the products (CQ) and (CQ10T,) obtained by the present invention have a strength close to that of the conventional product T6. is confirmed. Therefore, it is confirmed that the method of the present invention has substantially the same effect as solution treatment.

As is clear from the above description, according to the present invention, when casting a molten aluminum alloy, the conditions are as follows: a casting pressure of 300 KV6rA or less and a gate speed of 3 m/min.
See or less, it is possible to suppress the generation of cavities and blisters while increasing production efficiency compared to conventional gravity casting.Furthermore, since the clinging force to the mold is small, it can be easily taken out from the mold. Furthermore, according to the present invention, since the casting is taken out from the mold and quenched before the temperature reaches 350°C or less, the same effect as in 7 can be obtained by applying solution treatment, and furthermore, the second invention In this case, artificial aging treatment is applied after quenching, which has many effects such as further strengthening the product.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a mold used for carrying out the present invention, and FIG. 2 is a graph showing the differences between the conventional method and the method of the present invention. In addition, in the drawing, 1 is the mold, 3, 5.6 is the core, a is the natural cooling process, b is the solution treatment process, C is the artificial aging process, d
is the quenching process. Patent applicant Honda Motor Co., Ltd.

Claims (2)

[Claims] (1) Casting molten aluminum alloy at a pressure of 300 Tiy
The mold is pressurized and filled with a gate speed of 3 m/'sec or less, and after the filled molten metal has solidified, the casting is removed from the mold when the casting temperature does not drop to 350°C or less. A method for producing aluminum alloy castings, characterized in that the aluminum alloy castings are immediately quenched. (2) Molten aluminum alloy is pressurized into the mold at a casting pressure of 300%i or less and a gate speed of 3m/'sec or less, and after the filled molten metal solidifies, the casting temperature is 35%
Remove the casting from the mold when the temperature does not drop below 0℃,
Method 0 for producing an aluminum alloy casting, characterized in that the casting is immediately quenched and then subjected to artificial aging treatment.